[vdr] Advice on new motherboard, xineliboutput, vdpau, hdmi video & audio, etc.

Seppo Ingalsuo seppo.ingalsuo at iki.fi
Wed Aug 18 21:35:25 CEST 2010


On 18.08.2010 11:13, jori.hamalainen at teliasonera.com wrote:
> I also would like to remind the framerate issues. Naturally you decide 
> what
> is enough precision and quality for you.
>
> Computer hardware usually cannot provide 50.000Hz, 59.940Hz or 23.976Hz
> outputs to your TV/Monitor. This will cause some judder on display output
> as MPEG/AVC input-stream is not synchronized to output framerate.
>
>    
I have got "good enough" 50 Hz output to HDMI from Nvidia GS8400 DVI 
output with VDPAU. Typically there is small jump about every 10s with 
DVB SDTV content but it is visible only with graphic news scrollers. It 
is not annoying me that much. That is of course a very subjective matter.

> For example dedicated blu-ray player Philips BDP3000 had a 24.000Hz output
> (before firmware fix) which resulted a jumped frame every 42 seconds as
> real input stream is 23.976Hz. It was annoying after you noticed it. But
> luckily now it is fixed to real 23.976 output.
>
> With this bridge we come to VGA-hardware which might have 50.01Hz closest to
> 50Hz signal. So every 100 frames we get a jump in picture synch. Ever seen
> jumping camera panning while watching a film and got annoyed by it?
>    

Yes -- I have tried VGA but my one TV has only 60 Hz VGA mode that 
produces bad juddering picture. Then my other TV does not accept full HD 
modes via VGA. I also prefer the brighter colors and perfect pixels I 
get over HDMI.  Subjective things again ...
> For ATI cards there is a dynamic framerate fix, unfortunately there is not
> one
> for Nvidia cards. Nvidia has good HW acceleration but potentially bad
> output.
> With ATI vice versa.
>
> This ATI fix fixes 50.01 by dynamically reprogramming VGA timers so real
> output
> is 50.000Hz. (General description, the author can describe more if needed).
>    
I tried two years ago a motherboard with integrated AMD graphics with 
HDMI but bought soon the cheap NVidia GS8400 card because of problems: 
poor stability/wife acceptance factor,  tearing, blurry scaling etc. I 
am still using AMD stuff at work for desktop usage so I have seen the 
improvement in the open source drivers but I still feel I get better 
value for the money with NVidia stuff.
> So if you aim to HD with full HD quality I'd be carefull with computer
> outputs.
> My answer was to setup Popcorn hour to output 50.000Hz with TV-stuff.
> Unfortunately
> you lose some easy-of-use with VDR as you need to have separate layer to set
> up etc.
>    
I have also a PS3 and tweaked Mediatomb to serve the VDR recordings and 
some live TV channels over UPnP. It is slightly better with 576i50 -> 
1080p50 conversion than my HTPC but the difference is quite small. I 
guess that is "perfect" and comparable to the picture you get with 
Popcorn Hour.

The usability with PS3 is poor for Live TV because the channels are made 
to look like recordings and there is no p+ / p- channel surfing. The 
hack is not supporting DVB subtitles and sometimes I hear a non-prefferd 
sound track (the speech synth on the Dutch track). My family has learnt 
to use the hack while the HTPC is out of order but it is far from ideal 
solution. The fatty PS3 is also a bit noisy and consumes more power than 
a typical HTPC. I suppose the usability issues are not a problem with 
Popcorn if there is VDR usage dedicated firmware available?

> Also as original question came from Finland and if you use commercial HD
> channels
> they are (or at least should be) paired to your receiver.
>    

I see only some HD from DVB-S/S2.  Fortunately the kids channels that I 
subscribe do not require the pairing

Cheers,
Seppo




More information about the vdr mailing list